Bellatrix's Smile
by Scarlet Secret
Summary: Set postHBP. When the trio are invited to search the deserted castle for information they learn a deadly secret about the new Headmistress, something they could never have predicted but looking back they knew was always there.
1. Chapter 1

A/N: This is for everybody who through the series has stuck by Minerva McGonagall when, at times, she hasn't been the most obvious character to love. After the end of the series all the theories that have been made over the years will become redundant and I for one will miss that. This fic is an attempt to keep alive my personal favourite of the McGonagall theories. It won't be reveal until the end btw 

Harry had not intended to return to Hogwarts so soon.

After Dumbledore's demise the mood at Hogwarts had changed dramatically – gone was the lingering carefree laughter from those people who were determined to find some joy regardless of Voldemort's heightened terror campaign. The headmaster was gone and as much as Harry respected Professor – _No, Headmistress, _he reminded himself – McGonagall, he could not bring himself to go to the school, whilst she was finding her feet. Her incompetence, at least when compared to Dumbledore, was evident and he had been quite vocal about his concerns, which had left bad blood between the two of them. One of his biggest grievances had been her decision to close the school, which Harry (and several others in fact) had been quick to point out defied Dumbledore's last wishes, but she was the Headmistress and he had been powerless.

However, when Hermione had received a letter from the Headmistress offering her use of Hogwarts library for their quest Hermione had immediately accepted. She had, of course, already read a great deal of the books and certainly all of the interesting ones but McGonagall had promised Hermione use of the Restricted section as well. Hermione, it turned out, had read most of them too. McGonagall's final offer though had been too tempting to resist.

It was not common knowledge amongst students that the founders had their own library that only opened itself to the truly exceptional and those in particular need of their resources. "It's a little bit like the Room of Requirement" Hermione had explained. And so Hermione had Apparated to the gates of Hogwarts, dragging Ron and Harry with her. They had complained but when she pointed out it was Harry that was the one in need they had come quietly.

However the big problem was McGonagall could give them no indication of where the secret library was. Indeed they had not even seen her since they had arrived. And thus the trio found themselves walking down corridors they had never before seen in an attempt to find the room.

"I'm just theorising Harry! If it is like the Room of Requirement then we might need to think only about the room appearing for it to happen."

"I heard you the first time Hermione! How am I meant to think about the founders though, I don't know what they look like or anything!"

"Honestly! There's plenty of information about them in Hogwarts…"

"A History, thank you yes, we have been told about that book before."

"Ron, I'm only trying to help!"

"We've been at this for hours."

"Hogwarts is a huge place. There are hundreds of staircases and even Dumbledore himself never claimed to know about every single room in the castle."

"Yeah, well. He could have left a map of the rooms he DID know about, couldn't he?"

"Honestly Ron!"

"Accio wands!"

It had come out of nowhere and the three of them were completely taken aback when their wands went flying out of their respective pockets. They spun around and were immediately frozen by the sight of Bellatrix Lestrange.

"Bugger Merlin you lot can be tedious! And I've spent fourteen years talking to myself and the mice!"

She had not changed in Harry's estimation. Still the same talk, dark woman who had cackled wildly when she had killed her own cousin; the same woman who had tortured Neville's parents and mocked him mercilessly about it; the same woman who Hermione had always thought was vaguely familiar, though she couldn't place her at all. Through their moments of shock Bellatrix seemed to be growing bored by their slow reactions. It was Ron who recovered first.

"How did you get in?"

"I beg your pardon Weasley?"

He continued unperturbed.

"You can't have Apparated in and the barriers around the castle wouldn't have let you in. it's in Hogwarts: A History."

Hermione stared at him for several long beats, slowly a small smile formed on her face.

"You DID read it!"

"Quiet!"

With one quick flick of her wrist Bellatrix vanished their wands and began to advance on them. Harry had never felt such a coward in all his life but he reasoned it was the only thing he could do. With his seeker's reflexes he grabbed Ron and Hermione and pulled them forcibly down the nearest corridor. Bellatrix screamed in rage as her spell missed but they paid her no heed as they jumped to their feet and ran.

Next to him he heard Hermione mumble "We need to get to McGonagall's office."

_Dumbledore's office! _Harry thought. He felt a sudden surge of dislike for Minerva McGonagall that was completely perplexing. Rationally he knew she had done nothing wrong but she was easy to blame, after all it was on her watch that the most notorious Death Eater of the lot had slipped into Hogwarts. He felt a sudden surge from his scar and knew that Voldemort must have had big plans for Bellatrix tonight. The Death Eater in question was chasing them relentlessly through the halls and Harry briefly had to admit admiration for her tolerance levels. They were extraordinary, he and his friends were breathing heavily and moving on adrenaline but she seems indefatigable.

After what seemed like hours but was probably only five minutes they skidded to a halt before the stone gargoyle only to discover the staircase to the office already exposed.

"Oh no, she must have come here first!"

They tore up the stairs all of them shouting "Professor" and all forgetting that she now held a grander title. Upon reaching the office door they stopped abruptly – the sound of Bellatrix's footsteps had died.

"Has she stopped…?"

"Where's she…?"

"Shhhhh! We need to find McGonagall."

When they opened the door they froze immediately. They could not really have been more hocked if they had discovered their old Transfiguration Professor wearing Dobby's hats, Trelawney's shawls and dancing the meringue with Voldemort himself.

She was sat quite calmly in Dumbledore's old chair drinking tea from his bone china and reading a book Harry swore he had seen before. She looked up at their sudden appearance with mild surprise on her face, although she seemed completely unaware as to why they were there.

"What on earth is going on?!"

"Professor…"

"Headmistress, Potter!"

He was momentarily stunned by her outburst and the gleam in her eye which once again made Harry think he had done something wrong.

"Right yeah, Headmistress then. It's Bellatrix Lestrange. She's in the castle. She was chasing us but I think she's stopped."

"Probably knew we were coming to you". Ron offered by means of explanation.

Surprising them thoroughly once again McGonagall seemed to have minimal reaction to their news. She closed her book but did not put it in a position by which Harry could read the title and placed her teacup on the desk.

"Thank you for that confirmation of my ability to intimidate. It will make this much easier…much easier…" She muttered the last two words seemingly to herself.

With a supreme lack of concern for the fact a mad Death Eater was baying at her door McGonagall calmly stood and walked around to the mirror at the side of the room. Without another glance at them she began to adjust her hat. Harry could not contain himself any longer and his anger against her spilled out.

"What the hell do you think you're doing? She's out there! The woman that killed Sirius and did all that to Neville, they were you're students! You call yourself the Headmistress! What are you going to do about it!?"

Briefly, danger flashed in McGonagall's eyes when she spun around and spat, "She was my student as well!" at him, but she regained her aloof demeanour extremely quickly. All three were stunned into silence as she ignored them once more and walked back to Dumbledore's chair. Ron seemed to be slowly creeping into the corner of the room but it was Hermione breached the quiet at last with a calmer voice.

"Headmistress, something needs to be done. Bellatrix is down there, there are still other people in the castle. She seems to be afraid of you so there must be something you can do?"

McGonagall looked Hermione square in the eye and she seemed to have reverted into her lecturing voice when she said, "Actually Miss Granger, it is you three who must do something, that something be making a choice."

On their confused looks she continued.

"You can either go back downstairs and face Bellatrix or…" Her gaze did not waver from Hermione's, "…You can stay here and face me."


	2. Chapter 2

For a long pause Harry felt sure she must have been joking. They only flaw in his reasoning being that in nearly seven years of knowing her he had never seen Minerva McGonagall joke once. She simply could not be serious though.

Harry felt numb. This could not be happening. He couldn't comprehend what he had just heard but slowly, agonisingly it began to fit.

"Malfoy…?"

"As though he could trick the traitor into killing Dumbledore with the help of a barmaid too stupid to realise she has been under my control for thirty years."

"But you joined the fight!"

"And missed Alecto by miles. Of course you weren't paying attention to that were you Potter," she finally turned away from Hermione to glare at him with abject loathing. "But then you do miss a great deal that doesn't revolve around you and your precious Dumbledore!"

The silence that followed was deafening and Harry simply could not think of what to say. His mind began to frantically think back over the six years, certain he could not have missed anything that significant. Ron, once again, spoke first.

"The chess set."

For a moment Harry thought Ron had gone mad and began looking around the office for the item, wondering what on earth it could have to do with the situation at hand. McGonagall, however, seemed to understand Ron's words.

"Very good Mr Weasley. I knew you'd get there someday. Did you always wonder?"

Ron didn't answer, but closed his eyes and swayed towards the wall by which Dumbledore's chess set lay on a heavy table. For a brief second Harry thought he had been cursed, but Ron simply leaned against the wall and shook his head.

"Yes, I'd imagine it is rather irritating. Your own incompetence leading to a moment like this."

Hermione's sobs became audible and Harry remembered all the times his best friend had referred to the Professor's wisdom and trusted her judgement implicitly. To her it must have felt like the coldest betrayal

"What the matter Hermione…?" Harry was vaguely aware of the fact that the maniacal grin that spread across McGonagall's face made her look suddenly, extraordinarily like Bellatrix. "Cat got your tongue."

"Professor…how could you do this?"

Harry had a sudden recollection of the way his Aunt Petunia had broken her usually composed state to screech his true history at him when the unflappable Minerva McGonagall shot to her feet, hair falling loose, hat toppling off and looking thoroughly menacing to tell them what he assumed was the truth.

"Because Dumbledore always thought he was SO very untouchable! In everything! I fell in love with Tom Riddle and Dumbledore told me it was a silly, teenage infatuation and that Tom would be no good for me. He said that there were so many men who could treat a woman as wonderful as me properly, not like dirt, that's what he thought of Tom and me you see. Dirt."

"Tom Riddle? The Dumbledore knew you were working for him all along?"

"Oh no Potter, don't be stupid. It's your greatest fault, you know. You'll never be great unless you stop asking stupid questions." Here she laughed. It was the first time he had ever heard her laugh and he thought it was the single worst sound he had ever heard.

"Tom and I vanished for years, not a soul saw us and we were so very happy. Then we started our plan. The night I came to Dumbledore I was ragged and alone. Him being the fool he was he took me in immediately! Can you imagine how blind a man would have be to do that!? Of course he would _never _have suspected a woman, nobody would! I was weak and feeble and I simply HAD to have the greatest man of the age look after me! It helped that I was seven months pregnant, oh yes Weasley, pregnant! I never looked in the mirror, but I must have looked a state!"

Here she broke off and began to laugh wildly, looking right at them but somehow seeing straight through them.

"When the child was born Tom came to the school to try and claim the Defence Against the Dark Arts job…"

"I saw it! I saw the meeting…"

"Dumbledore again I expect. Trying to teach you about _that nasty Slytherin boy_! He had a habit of calling him that when in my company, I'd imagine he still told his Gryffindors that."

For a long time she was silent, gazing at the portrait of the late Headmaster with an unreadable expression. Harry noticed Ron shuffle his feet again.

"Professor," Hermione said. "What about the child?"

"Taken to a good pure-blood family. As though you hadn't guessed that already Miss Granger."

Hermione wiped at her eyes furiously with her right hand and Harry saw specs of blood from where her fingernails had dug into her palm. There was steel in her voice now though.

"Yes, I had noticed a certain similarity in your spell-casting techniques. And she looks like you. Same smile; I noticed that half way though fifth year."

Harry was completely confused. Before he could ask though McGonagall turned her gaze from the slumbering Headmaster and looked at them all.

"I'll give you the choice again. Face me; or face Bellatrix."

"We don't have our wands."

As the 's' left his mouth Harry watched all three of their wands materialised in McGonagall's hands before she uncaringly threw them in her roaring fire.

"I know that Potter," she said with sarcasm worthy of Snape.

"Oh Professor Snape, by the way," she continued casually, ignoring their horrified expression as they watched their wands turn to ash. "Turned out to be your ally all along. A most unfortunate business really. Tom wasn't pleased at all."


	3. Chapter 3

A smile graced her features again as she thought of Voldemort with what Harry assumed was reverence. His anger boiled to the surface again and for the briefest moment he could not believe he was distraught at the death of Snape.

"Couldn't have that could we? Your dear Dark Lord being sad…!"

Her reaction was lightening quick. Her head spun towards him and, seemingly to momentarily forget she was a witch, she began towards him with fury in her eyes.

"He is not my Lord! I am his equal…!"

Out of nowhere Ron had lurched forward to Harry and Hermione's right, using all of his might to hurl the table and chess set at McGonagall who, completely caught unawares and without her wand, was hit violently and flew yards over the desk with the table. Ron didn't waste a second but grabbed the other two and dragged them down the stairs. Hermione pulled at him when they reached the bottom of the stairs and whispered "Bellatrix."

But Ron seemed beyond caring. They ran through the corridor to the right and thankfully seemed to have escaped Bellatrix momentarily. She obviously had not been expecting them out of McGonagall's office so soon. Harry turned to Ron and asked one of the questions that was burning in him.

"The chess set?"

Aloud it sounded more ludicrous than he thought it would.

"I suspected something. But never this. When we went though the trap door in our first year," Ron was beginning to pant now. "All the other stuff had been used; the key with wings, the troll, even the potion, but the chess set was waiting for US."

"What?"

"Harry, who did we tell that we knew about the Philosopher's Stone before we went down?"

_No! But it makes sense. _A little voice told him, the same voice that sounded strangely like the sorting hat. _Think about it Harry…_

And he did. As they ran he felt the blood pumping through his veins and could hear it thumping against his eardrums, but at the same time Ron and Hermione were contributing incidents that suddenly took on a new meaning.

"When Crouch Jnr was killed by the Dementors…?"

_As if Minerva McGonagall couldn't conjure a Patronus when I could do one!_

"She closed Hogwarts…"

_Dumbledore's last wish._

"She wanted to know all about the Horcruxes Harry, remember, you told us?"

_Needed to know how much information I had._

"And Umbridge and her cronies stunned her so easily…"

"_As if one of them could have Stunned Minerva McGonagall face on by day light…"_

"She helped the fake Moody Harry, must have done…"

"…_talking loudly with Professor McGonagall about Gillyweed…" he had said._

"When Riddle's Diary got rid of Dumbledore, she was Headmistress. Tried to close Hogwarts as well then, remember Harry…"

_She let Ginny get taken!_

"And how many times have you nearly been killed playing Quidditch, and she put you on the team…?"

_Youngest player in a century._

Hermione suddenly came to a halt by his side.

"Harry, she was always discrediting Professor Trelawney, and I believed her! But where is she? All the other teachers have gone home, it was in the Prophet but Trelawney isn't allowed to leave the castle. Voldemort must know the prophecy!"


	4. Chapter 4

Without stopping to draw what little breath their lungs could hold the trio began racing towards North Tower. Their assumptions about Bellatrix had not been correct however, soon enough they could hear her boot clicking frantically on the ground as she chased them. But there was an extra rhythm this time, quieter, very quiet, but unmistakably there, a sort of light thudding that was much more rapid that Bellatrix's pace.

For a moment Harry thought it must be his heart before he realised McGonagall was now on their tail in her Animagus form. They would never outrun her forever. Harry dreaded to think how close McGonagall was as he could hear Bellatrix's gleeful voice echoing through the corridors.

"My mommy's going to kill you Potter! She'd going to chop you up and feed you to the werewolves. Mmmmmm, saviour- skin!"

Her cackle followed them and for the first time that evening they achieved some luck, North Tower was before them. Smiling for what felt like the first time in hours, Harry, Ron and Hermione ran up the stairs to the Divination tower just as a grey tabby with spectacle marks leapt at them from behind. She landed on the back of Ron's head but he wrenched her from him, suffering some deep scratches as he did and threw her into the air. She landed raced at them again but they had already crossed the threshold and she was repelled by and invisible wall from entering the tower. Confused they pulled the attic door firmly shut and frantically pulling a small bookshelf on top of the door, knowing rationally it would stop McGonagall and Bellatrix for all of a nanosecond.

"Professor Trelawney!"

They dashed into the classroom but found the teacher notable by her absence, although a faint spell of incense and sherry lingered in the room. Although none of them had ever been there they knew her personal quarters were connected to her teaching room, making her unique as a member of staff. Banging on the door first they gave up politeness and burst through the door to find the professor sat at a desk-side window, writing a letter.

"Professor…!"

"I heard you the first time Miss Granger."

Her ethereal tones had completely vanished, as had her scarves and Harry registered that she looked remarkably normal. He thought he must have been dreaming, all this treachery simply could not be happening. Not only had the granite-like Professor McGonagall turned out to be traitor, but the frankly useless Trelawney was completely calm about it. Surely she couldn't be against them too.

"It's McGonagall. She's a Death Eater."

This at least seemed to raise Trelawney's head from her letter, but she was yet to turn to them; Harry was not for risking this again tonight and marched forward, grabbed her by the shoulders and spun her round.

He mastered his start when he realised she was not wearing any glasses, but also she seemed completely unperturbed at being man-handled by a student who had not particularly liked her. In fact, for a moment, she seemed to have the same twinkle in her eye that Dumbledore had had, but Harry ignored this and tried to employ his amateurish Legilimency skills on the Professor but found himself blocked, not by the similar bars of Occlumency, but something entirely different.

Smiling Trelawney obliged his confusion.

"It's the Seers mind Harry. You can not see what I see because the visions do not belong to me. My mind is not truly my own."

Hermione strode forward urgently now, seeming to forget the last time she had spoken with Sybill Trelawney was over three years ago and it had not ended well.

"Professor, we need you help. McGonagall and Bellatrix Lestrange are right outside your door."

At the mention of Bellatrix Trelawney started and flew to her feet, grabbing her wand off the desk, and began pulling Ron away from the door to join the others.

"I had not anticipated _her_ being here also. As you may have seen Minerva is not allowed to enter my rooms, Albus long ago separated these rooms from the rest of the castle; they are an entity unto themselves. And as such I may keep away intruders, even if they happen to be the Headmistress of Hogwarts."

"Or a High Inquisitor?" Ron asked suddenly, seeming to regret it seconds later. Trelawney looked impressed.

"Here was I believing nobody had noticed my continual presence in the school that year. Never mind though, Delores Umbridge, despite what my delicate condition may have suggested was nothing. This is Bellatrix Lestrange, and she may be able to enter. All of you get behind me."

Having no choice but to stand behind her for the time being they did so and Harry noticed with some guilt that the Divination Professor looked more emaciated than ever before. Since the war had began he had given her no thought – granted he had given her little before but still – and here she was trapped in the attic whilst a Death Eater McGonagall and Bellatrix hounded her door. She must have been terrified. If she had, however, she gave no sign of it now. Slowly edging towards the door to her living quarters, wand held high and protecting the trio, he couldn't help but think that Dumbledore would be proud of her.

There was a strong thud at the door to the attic outside and Hermione let out a small scream and clung to Professor Trelawney's shoulders. Harry noticed vaguely that they were the same height now and there was a certain resemblance between them. He made a mental note to tell them both later when they had escaped, he was sure they would both laugh about it. The thud grew louder and louder before a great crash announced the admittance of Bellatrix into the attic.

"There through here mummy, with the Seer."

"Good girl Bella, bring them all out to me…"

"Can't I kill one!"

"NO! I have scores with all of them. You hear me don't you Sybill! I'm coming to get you!"

The maniacal laughter pierced the silence and nobody was sure whether it came from Bellatrix or McGonagall. It was very likely that it was both of them. Without warning Trelawney spun around and for a brief second Harry's stomach dropped and he thought she had betrayed them too, but she began pushing them towards the fire. She threw some Floo powder into the flames, pushed Hermione and Ron in whilst muttering clearly "Ministry of Magic".

They vanished before they could open their mouths to protest and she turned to Harry with a look of finality on her face.

"Go Potter. Bring the Aurors."

With that she pushed him in and he felt himself vanish. When he arrived at the Ministry it was to find himself on the floor with the green fire still burning, immediately he put his head into the flames and went back to Trelawney's tower to get her through.

Bellatrix was through the door and battling with Trelawney and it was plain to see that while the teacher was no novice with a wand she had never had need to fight battles like this before. He had to get her out of there. However it was Bellatrix who noticed him first.

"Ha ha! Little Potter's come back to save you Seer!"

A more experienced dueller would have ignored Bellatrix's taunts but in the brief second Trelawney took to turn her head the Death Eater sent her final curse. Harry saw the green light first.

"_Professor!"_

"Professor. Professor."

"Sybill for Merlin's sake wake up!"

Sybill Trelawney opened her eyes not to see the cold, dead ones of Bellatrix Lestrange but the faintly amused, twinkling blue ones of Albus Dumbledore and a quick glance across the room showed her Minerva McGonagall, looking as staunch as ever. If ever a person were not a Death Eater it was she.

Sybill couldn't quite believe it. She had dreamt all that – but with such clarity, it had happened.

"I had the oddest dream."

"I expect we were both there were we." McGonagall's usual brisk, faintly sarcastic voice made wonder where her sub-conscious had conjured the voice which had threaten her and cackled with Bellatrix.

"No, you were. Albus you were…well dead."

She noted vaguely that Dumbledore didn't seem half as started by this news as McGonagall did.

"Yes, something to do with the Malfoy boy…"

"Hmmm, Draco Malfoy. Interesting. I must speak with Severus. If you excuse me ladies."

He had been absent for all of three seconds before…

"What utter rubbish! The Malfoy boy indeed! His father was only yesterday put in Azkaban somehow I do not think he needs you balderdash prediction over his head also."

Sybill began to get irate. She had not claimed it was a prophetic dream, but every attempt at friendliness she attempted in the staff room was met with coolness and ridicule these days. Now Umbridge was leaving she felt happy again and McGonagall was not going to ruin her day.

"Would you care to know the specifics of my dream Minerva? There was some highly informative images of yourself…and your daughter."

Sybill would be the first to admit her own eyesight was not the best but no powers on the earth would convince her what she had just seen in McGonagall's eyes had not been fear. It was gone quickly but it had been there and was now replaced with the usual stony indifference.

"I have no idea what you are talking about Sybill."

There was silence for several seconds during which Sybill wondered briefly whether McGonagall was about to kill her. To alleviate her fears the staff room door came bursting open and Madame Hooch practically skipped inside.

"Afternoon you two. Absolutely bloody glorious weather isn't it? And we've finally got rid of the old toad. I think this a good day to give young Potter his Broomstick back and maybe I'll get the teams together later for a friendly end of term game? What'd reckon Minerva? Think they'd go for it, after the news and all?"

Whilst she had been speaking Sybill had backed slowly into her seat, allowing the Quidditch Mistress to take away Minerva's notice. Unfortunately for both of them Hooch could be notoriously clumsy and sent a mug toppling straight towards Minerva who tried to shield her face and soaked her left sleeve through. she grabbed it as though it were on fire. Her shrieks were piercing.

"Madame Hooch! I would very much appreciate it if you could watch what you're bloody well doing next time! Clumsy fool, you've scolded through my skin!"

With that Minerva left and thoroughly scared Divination Professor and an utterly confused Flying Instructor. Hooch fell into the seat next to Sybill and in a perplexed voice spoke.

"It's funny, I could have sworn that water was cold."


End file.
